Thulium Alkylidene Complexes: Synthesis, X-ray Structures, and Reactivity

The first thulium alkylidene complexes (2 and 5) were
synthesized using a stable dianionic ligand as carbene precursor
and were characterized by X-ray diffraction analysis. These
complexes were shown to involve metal−carbon double-bond
character by their reactivity toward benzophenone. A solid-state dimorphism revealed the participation of a π-overlap
between the carbon and the thulium centers in the stabilization
of the homoleptic complex 5.